Every man over the age of 45 is at risk for prostate cancer. Two-dimensional (2D) trans rectal ultrasound (TRUS) guided biopsy is the standard method for prostate cancer diagnosis. A critical problem of this TRUS- guided biopsy approach is its significant sampling error and its low sensitivity (24%-52%). Current biopsy approaches may miss up to 30% of prostate cancer. Nevertheless, more than 1.2 million prostate biopsies are performed in each year and the biopsy cost is more than two billion dollars. Innovative image-guided biopsy technology that can improve cancer detection can have significant impact on the management of this disease that affects one in six men. The objective of the proposed study is to evaluate a new, molecular image directed, three-dimensional (3D) ultrasound guided biopsy system in human patients. At our NIH-funded Emory Molecular and Translational Imaging Center, it has been shown that PET/CT imaging with a new, PET molecular imaging agent i.e., FACBC, is more sensitive than the FDA-approved SPECT/CT in prostate cancer detection. FACBC images showed higher focal uptake in tumor foci than in normal prostate and thus could be ideal information to direct targeted biopsy of the prostate. This newly developed biopsy system has a unique feature that FACBC PET/CT images can be registered with 3D ultrasound images, as a result, a suspicious PET lesion is superimposed over the real-time ultrasound data; and the fused image is then used to direct biopsy needles to tumor targets. The hypothesis of the study is that FACBC PET/ultrasound fusion guided biopsy can detect more cancer per core than the standard 12-core TRUS guided biopsy. The specific aims include: 1) To develop the workflow for performing deformable registration and fusion of FACBC PET/CT and 3D ultrasound images of human patients, and 2) To perform FACBC PET/CT directed, 3D ultrasound-guided biopsy and determine if targeted fusion biopsy can detect more cancer than 2D TRUS-guided biopsy. Thirty six patients, who have suspicion of recurrent prostate cancer after definitive therapy such as radiotherapy, will be recruited into this study. Approximately hal of the patients will have positive imaging findings and will undergo 2D TRUS-guided biopsy as well as PET/ultrasound fusion biopsy. The proposed study will be the first-in-human trial that uses PET/CT imaging to direct 3D ultrasound-guided biopsy of the prostate. The multimodality imaging approach will combine the high sensitivity from PET and real-time information from ultrasound for improved cancer detection. This early-phase clinical trial will help transform the field from the current blind biopsy to future targeted biopsy and result in the change of prostate cancer management. The new biopsy technology can have an immediate impact on patient care by improving the detection and diagnosis of prostate cancer.